Electrical leakage of an electrical appliance or induced electricity generated on a shell when the electrical appliance is in use, can be led to earth through a grounding line, so as to avoid personal electric shock, which can protect personal safety. However, the grounding line may be disconnected or poorly contacted which may lead to security incidents. Thus, there is a need to detect whether the grounding line is well connected.
In a conventional technology, grounding detection requires a special instrument, and needs to be carried out under a power-off state of the electrical appliance, and the detection method is complicated. Further, the conventional detection method can only detect whether the grounding line is in good condition, but can not detect a poor contact of the grounding line with an external ground.